This invention relates to an ultraviolet absorber and a coating material containing the ultraviolet absorber.
It has hitherto been practiced to employ an organic ultraviolet absorber in conjunction with an acrylic resin for use as an ultraviolet protective coating. However, a problem is presented that, on prolonged use, leak out of the ultraviolet absorber or light deterioration of the polymer used as a basic material is produced to deteriorate the performance. For overcoming this drawback, attempts have been made in improving resin components or in employing an antioxidant in combination, as disclosed in Japanese Laid-open Patent Application No. 63-43972 (1988). Attempts have also been made in copolymerizing a basic polymer material with an organic ultraviolet absorber having methacryloyl groups for eliminating leak out (Japanese Laid-open Patent Application No. 6-88064 (1994)). However, since numerous ester bonds are contained in the main chain of the materials employed, Norrish type reaction is produced or the materials cannot be used under high temperature environments exceeding 200.degree. C.
Also, a number of attempts have been made for introducing functional groups having silyl groups by hydrosilylation, as disclosed in Japanese Laid-open Patent Application No. 2-243695 (1990). However, difficulties are met in multiple application of silicone coatings employing silylated ultraviolet absorbers.